Then a man who is ceremonially clean is to gather up the ashes of the heifer and store them in a ceremonially clean place outside the camp. They must be kept by the congregation of Israel for preparing the water of purification; this is for purification from sin.
Jewish Publication Society of America Version (JPS1917) - Numbers 19:9 >And a man that is clean shall gather up the ashes of the heifer, and lay them up without the camp in a clean place, and it shall be kept for the congregation of the children of Israel for a water of sprinkling; it is a purification from sin.